1. Field
The present invention relates to a liquid cooling device, and more particularly to a liquid cooling device used to cool a heat-generating device mounted within a computer system.
2. Related Art
Boom of electronic technology promotes quick evolutions and rife applications of computers. Nowadays, personal computers are prevalently used in a variety of fields concerning study, work and life of human. A central processing unit (CPU) is a core of a computer system, as we know. Computers are ceaselessly updated to have the CPUs in higher frequency and higher speed. CPUs of these computers accordingly generate an increasing amount of heat which must be timely removed to enable the CPUs to retain stable operation.
Recently, some kinds of liquid are widely used as heat-transfer media contained in cooling devices to convey heat from one place to another place. Water is a preferred one among these kinds of liquid, because water has great specific heat and does not contaminate environment. Another reason for water being popular in liquid cooling system is that water has a low cost.
Taiwan Patent Issue No. 555073 disclosed a liquid cooling device. The cooling device comprises a heat absorbing box for containing liquid therein, a pump and pipes connecting the pump to the box to form a liquid circulation loop. A plurality of ribs is formed in the box to enhance heat-exchange between the liquid and the box. Unfortunately, the box itself is too small in volume to provide enough heat-exchange area. Additionally, most heat absorbed by the box is dissipated to environment by means of circulation of the liquid; thus, speed of the heat dissipation is restrained.
China Patent Issue No. 2612070 also taught a liquid cooling device. The cooling device provides a larger heat-exchange area in comparison with the cooling device disclosed in Taiwan Patent Issue No. 555073. However, the cooling device is heavy, and its weight is totally exerted to a printed circuit board on which the cooling device is positioned. The printed circuit board is subject to damage as a result of the overload of the cooling device. Secondly, heat-convey pipes in the cooling device are designed to exchange heat with a heat sink by repeatedly extending through the heat sink, whereby the heat-convey pipes must be formed with a large number of U-turns. Such a design makes the heat-convey pipes expansive and makes the assembly between the heat-convey pipes and the heat sink difficult and laborious. Furthermore, the U-turns of the heat-convey pipes are subject to corrosion since they create areas of stress concentration.
Moreover, each of the cooling devices above-mentioned utilizes a pump to enhance the circulation of the liquid in the cooling devices. Pumps are expensive devices, and consume power when operate.